Sync zlib sources with GCC, upgrading to 1.2.10.

Changes in 1.2.10 (2 Jan 2017)
- Avoid warnings on snprintf() return value
- Fix bug in deflate_stored() for zero-length input
- Fix bug in gzwrite.c that produced corrupt gzip files
- Remove files to be installed before copying them in Makefile.in
- Add warnings when compiling with assembler code

Changes in 1.2.9 (31 Dec 2016)
- Fix contrib/minizip to permit unzipping with desktop API [Zouzou]
- Improve contrib/blast to return unused bytes
- Assure that gzoffset() is correct when appending
- Improve compress() and uncompress() to support large lengths
- Fix bug in test/example.c where error code not saved
- Remedy Coverity warning [Randers-Pehrson]
- Improve speed of gzprintf() in transparent mode
- Fix inflateInit2() bug when windowBits is 16 or 32
- Change DEBUG macro to ZLIB_DEBUG
- Avoid uninitialized access by gzclose_w()
- Allow building zlib outside of the source directory
- Fix bug that accepted invalid zlib header when windowBits is zero
- Fix gzseek() problem on MinGW due to buggy _lseeki64 there
- Loop on write() calls in gzwrite.c in case of non-blocking I/O
- Add --warn (-w) option to ./configure for more compiler warnings
- Reject a window size of 256 bytes if not using the zlib wrapper
- Fix bug when level 0 used with Z_HUFFMAN or Z_RLE
- Add --debug (-d) option to ./configure to define ZLIB_DEBUG
- Fix bugs in creating a very large gzip header
- Add uncompress2() function, which returns the input size used
- Assure that deflateParams() will not switch functions mid-block
- Dramatically speed up deflation for level 0 (storing)
- Add gzfread(), duplicating the interface of fread()
- Add gzfwrite(), duplicating the interface of fwrite()
- Add deflateGetDictionary() function
- Use snprintf() for later versions of Microsoft C
- Fix *Init macros to use z_ prefix when requested
- Replace as400 with os400 for OS/400 support [Monnerat]
- Add crc32_z() and adler32_z() functions with size_t lengths
- Update Visual Studio project files [AraHaan]

zlib/test/example.c

@@ -1,5 +1,5 @@
 /* example.c -- usage example of the zlib compression library
- * Copyright (C) 1995-2006, 2011 Jean-loup Gailly.
+ * Copyright (C) 1995-2006, 2011, 2016 Jean-loup Gailly
  * For conditions of distribution and use, see copyright notice in zlib.h
  */
 
@@ -26,13 +26,13 @@
     } \
 }
 
-z_const char hello[] = "hello, hello!";
+static z_const char hello[] = "hello, hello!";
 /* "hello world" would be more standard, but the repeated "hello"
  * stresses the compression code better, sorry...
  */
 
-const char dictionary[] = "hello";
-uLong dictId; /* Adler32 value of the dictionary */
+static const char dictionary[] = "hello";
+static uLong dictId;    /* Adler32 value of the dictionary */
 
 void test_deflate       OF((Byte *compr, uLong comprLen));
 void test_inflate       OF((Byte *compr, uLong comprLen,
@@ -59,13 +59,13 @@ void *myalloc(q, n, m)
     void *q;
     unsigned n, m;
 {
-    q = Z_NULL;
+    (void)q;
     return calloc(n, m);
 }
 
 void myfree(void *q, void *p)
 {
-    q = Z_NULL;
+    (void)q;
     free(p);
 }
 
@@ -432,7 +432,7 @@ void test_sync(compr, comprLen, uncompr, uncomprLen)
     d_stream.next_out = uncompr;
     d_stream.avail_out = (uInt)uncomprLen;
 
-    inflate(&d_stream, Z_NO_FLUSH);
+    err = inflate(&d_stream, Z_NO_FLUSH);
     CHECK_ERR(err, "inflate");
 
     d_stream.avail_in = (uInt)comprLen-2;   /* read all compressed data */
@@ -573,7 +573,8 @@ int main(argc, argv)
     }
 
 #ifdef Z_SOLO
-    argc = strlen(argv[0]);
+    (void)argc;
+    (void)argv;
 #else
     test_compress(compr, comprLen, uncompr, uncomprLen);